The broad goal of this study is to determine whether the functional activity of nervous tissue influences the metabolism of its functionally important proteins. This will be investigated by studying the synthesis, processing, and transport of a characteristic group of low molecular weight proteins in identified neurons of the abdominal ganglion of Aplysia californica. In previous work, I studied the characteristics of synthesis and processing of these proteins, and the current period will begin with a study of their axoplasmic transport. I then intend to determine whether their metabolism is regulated in accordance with the neuron's functional activity, specifically whether synaptic activation or modifications of secretory rate can influence their rate of passage through the metabolic sequence. I also expect to obtain additional data on the structure of these neuron-specific proteins.